I propose to examine the relationship between receptive field plasticity and learning in the hippocampus and entorhinal cortex. More specifically, I plan to collect data from large numbers of single neurons located in the CA1 region of the hippocampus and in the entorhinal cortex while rats are learning a task. In addition, I will work to develop a set of analytical tools based on an adaptive point process filtering algorithm previously derived in Dr. Brown's laboratory. This algorithm will allow us to accurately characterize both the changes in the spatial receptive fields that are thought to occur during learning as well as any changes in spike timing that may be present. The goal of this combined experimental and analytical approach is to accurately characterize receptive field plasticity in CA1 and the entorhinal cortex and to thereby better understand the relationship between behavior and neural activity in the hippocampus and entorhinal cortex.